genset smooth operation.

[uppercut]

i have been asked to look at a problem were a generator comes on line via a time clock. it is a simple 2 contactor changeover system with a mains failure unit. the problem is that it is in a petrol station with incandescent ligting throughout, and when the changeover takes place the lights require a electronic/warmup period, leaving the place in darkness for a while. i had thought of syncing the gen to the mains running in parrallel then dropping out the main contactor. can i re-sync back to the mains then drop out the gen? or any wiring modification you can think of, like staggering the lights between mains and gen power.?

 

[mpparent]

If you are going to try a closed transition process, I'd definitely make sure your equipment is braced for such a process, ie check the AIC's of your equipment and make sure you have a fault study done. The only thing I'm not clear on is if you have incandescent lighting, why is there a warm up period? If you had fluorescent or HID I would understand....

MIke

 

[electrageek]

This the right place to ask this kind of question. We have alot of experts in this arena. This is not any different then other synchronizing application. You must have a synchronizing breaker on both sides (a breaker capable of closing in a short period of time cycles). You will also have to be sure that the Engine control system is capable of connecting to a Utility grid with speed droop control rather then only Isochronous control and that the Voltage regulating system is also capable of connecting in parallel with the Utility (voltage droop control). Since this is an automated process then you will need an autosynchronzer with the Generator speed regulator capable of accepting the necessary speed raise and lower commands. The same is true for the voltage regulator. Then you will need a synch-check relay to protect for an autosynchronizer failure. You will also need a power relay to allow for separation from the Utility when the power across the Main breaker reachs zero power. You will need the same type of power relay mounted on the Generator to provide the same signal when you want to switch back to Utility power (i.e. open the Generator Breaker when the power through the breaker gets to zero. These days we would typically use a small PLC to do the sequencing and control (i.e. breaker close and trips, monitoring status, and some protection). The last big question is what does the local Utility think about your paralleling with their system. Do they have a policy or set of rules for allowing small power producers to parallel with the grid. Hopefully they don't have a problem with a short synchronizing period with the idea of testing a local Generator set. So in short yes it is possible to do what you mentioned.

 

[PAFred]

Gentlemen wouldn't it be much simpler to just install inphase monitors on both sides. This should make it possible to cause the generator to start but wait for sine wave matching before the ATS could do the transfer and like wise coming back?

If the power went out all together it wouldn't matter if the lights had to warm up.